Police in Virginia Beach cannot determine a motive for a city engineer’s rampage in 2019 that killed 12 people in the municipal building where he worked, according to the city’s final investigative report released Wednesday. “Despite exhaustive investigative work and in spite of unsubstantiated rumors and accusations, it appears we may never know why he committed this heinous act,” the report’s conclusion states. The 24-page report says shooter DeWayne Craddock did not leave a note or “any other account that would explain his actions.” “There were no common characteristics among the victims who were killed and injured relating to their age, race or gender,” the report adds. Craddock had worked in the city’s public utilities department for more than nine years. He killed eleven co-workers and a contractor who was getting a permit. Four others were seriously wounded and a police officer responding to the shooting received a bullet in …